Moparts
Broken tranny tailshaft housing question
Posted By: dragnduster
Broken tranny tailshaft housing question - 09/28/12 04:04 PM
I was making a pass yesterday and after I let off the throttle and was coming to a stop all of the sudden I heard a banging noise that lasted a couple of seconds and then went away. The car seemed to drive just fine and after I parked it and was checking things over I found a small amount of tranny oil under the car. I looked closer and found that the tailshaft housing had broke completely off just behind the tranny mount and had been just spinning with the yoke. It slid back into place just fine with no binding on the yoke. I am kinda baffled on what would cause it to break. Anyone ever seen this happen before and have any ideas? Thanks for the help.
Posted By: Al_Alguire
Re: Broken tranny tailshaft housing question - 09/28/12 04:11 PM
Have the driveshaft checked to ensure it is balanced. In my experience 99% of the time a broken tailshaft is caused by a driveshaft issue.
Posted By: dragnduster
Re: Broken tranny tailshaft housing question - 09/28/12 04:17 PM
That's a good idea, it is an all brand new shaft with just 5 runs on it but that don't mean it couldn't be the problem. Will breaking the housing like that cause any other problems with the tranny that I should check for or can I just replace the housing?
Posted By: Max Wedge Savoy
Re: Broken tranny tailshaft housing question - 09/28/12 04:19 PM
Lot's of variables here. Do you run rubber motor mounts or solid? Motor plate? Mid plate? Poly trans mount? If you run solid motor mounts or a motor plate and you use a poly trans mount there isn't enough cushion in that hard trans mount to give and the weakest point of the extension housing is right behind the webbing, probably where yours broke.
An out of balance driveshaft wouldn't have much of anything to do with it. The bushing inside the extension housing rides on the yoke which is attached to the output shaft.
Posted By: RADAMX
Re: Broken tranny tailshaft housing question - 09/28/12 04:23 PM
I have done that with a tight u-joint . make sure the u-joints move full swing freely. also if this is a new set up check travel to make sure you are not bottoming it out or Pulling it out to far
when I broke mine I was able to just replace the tail housing.
Posted By: dennismopar73
Re: Broken tranny tailshaft housing question - 09/28/12 04:25 PM
Yes need to check the out put shaft!
I have never broke one, but I have seen plenty of others tho!!
Check the rear mount for movement,
A motor can ' charge ' forward under de-accell if the drive shaft is to short can cause issues,, same as charging forward under heavy load, bent drive shaft, bad u joints,,
look for binding in the shafts movement area!!
Posted By: dragnduster
Re: Broken tranny tailshaft housing question - 09/28/12 04:35 PM
I run a solid mounted engine plate with the spool style factory rubber tranny mount. I have run that same setup on several other cars over the last 25 years with good luck but maybe this time is different. U-joints didn't seem overly tight but I will recheck. The yoke wouldn't be able to bottom out but it ended up hanging out about 3/4" more than I would have like it to be when the car is at rest, so maybe it slipped a little to far out and caused the problem. Wouldn't it slip out of the tranny more on decel and into the tranny on excelleration?
Posted By: Al_Alguire
Re: Broken tranny tailshaft housing question - 09/28/12 04:38 PM
Well yes a lot of things can cuase this problem but I have seen a LOT of Mopar tailshaft housing break and all but 1 were from the driveshaft. Either to long, or two short or not balanced. With balance being the usual cause of failure. The fact that it is new means little unfortunately these days. Since it is a new shaft and this occurred it woudl be where I would start. Assume this car was working with a different set up before??
Posted By: dragnduster
Re: Broken tranny tailshaft housing question - 09/28/12 04:43 PM
Lots of good ideas to check, thanks for all the help. Yes the car was working good before but it was a small block car then with all factory mounts. When I put the 440 in I decided to put in a new drive shaft with it since the old one was just that "old". I have no forward/backward travel limits on this setup, could that be an issue?
Posted By: an8sec70cuda
Re: Broken tranny tailshaft housing question - 09/28/12 04:50 PM
Quote:
Well yes a lot of things can cuase this problem but I have seen a LOT of Mopar tailshaft housing break and all but 1 were from the driveshaft. Either to long, or two short or not balanced. With balance being the usual cause of failure. The fact that it is new means little unfortunately these days. Since it is a new shaft and this occurred it woudl be where I would start. Assume this car was working with a different set up before??
I've broken two tailshaft housings and both times the cause was a twisted driveshaft.
Posted By: dennismopar73
Re: Broken tranny tailshaft housing question - 09/28/12 04:57 PM
Quote:
I run a solid mounted engine plate with the spool style factory rubber tranny mount. I have run that same setup on several other cars over the last 25 years with good luck but maybe this time is different. U-joints didn't seem overly tight but I will recheck. The yoke wouldn't be able to bottom out but it ended up hanging out about 3/4" more than I would have like it to be when the car is at rest, so maybe it slipped a little to far out and caused the problem. Wouldn't it slip out of the tranny more on decel and into the tranny on excelleration?
It will and can travel either direction equally! under accell it will try to push the shaft into the trans, under de accell it will pull it out, depending on the 'roll' of the suspension .
I would look at the balance, and see how straight the shaft is,, I had a new shaft and it was bent , got it from a drive shaft co out of Florida, never got in because I checked it out, ! 
Posted By: bentwheel43
Re: Broken tranny tailshaft housing question - 09/28/12 05:29 PM
I broke 3 & 4 rearend yokes because 1" to long.
Posted By: mopar400
Re: Broken tranny tailshaft housing question - 09/28/12 05:59 PM
I had this issue with too much pinion angle. The car was smooth going down the track but when I let off the gas I was getting a vibration. The pinion would fall on decel. and put the rear joint in a bind. Too many passes before I could get it fixed caused the tail housing to crack by the speedo hole.
I ended up winning that day but was dripping trans. fluid on the last pass!
I was a young kid and had set the pinion angle up incorrectly. Lesson learned!
Kevin
Posted By: John_Kunkel
Re: Broken tranny tailshaft housing question - 09/28/12 08:30 PM
Quote:
An out of balance driveshaft wouldn't have much of anything to do with it. The bushing inside the extension housing rides on the yoke which is attached to the output shaft.
Huh? 
Posted By: Blown 68 R/T
Re: Broken tranny tailshaft housing question - 09/28/12 08:42 PM
I had a problem with a new shaft it wasn't balanced properly also check to make sure it was measured right,i.e maybe too short, how far back is the yoke sticking out of the housing?
Posted By: dragnduster
Re: Broken tranny tailshaft housing question - 09/28/12 09:46 PM
I will have to get a measurement when I get home, I forget what it was off the top of my head(old age I guess). Sounds like I will make a point of getting the driveshaft rechecked for balance and straightness and hook up some travel limiters on both sides of the motor. I did have to readjust the pinion angle with this rear end I put in and I have it at 3* down with the car at rest on the tires. By the way it is a leaf spring car.
Posted By: oldtimer5151
Re: Broken tranny tailshaft housing question - 09/28/12 10:08 PM
What leaf springs do you have?
Posted By: Sport440
Re: Broken tranny tailshaft housing question - 09/28/12 10:26 PM
Yep, alot of variables. Bent shaft, out of balance shaft, to short of shaft, binding pinion angle issues, tranny and engine bolted together in a stressed condition alignment, etc.
The shaft does pull out on decell, if it comes out to far it can shake and break the tail housing.
Or a combination of any of the listed variables can stack up and break the housing too.
With your spool mount I think you would have enough driveline flex to avoid a stress break. Id focus on blance, length and staightness.
Posted By: dragnduster
Re: Broken tranny tailshaft housing question - 09/28/12 10:39 PM
Leaf springs are a factory A body spring with 5 leafs, I put 2 stock type spring clamps on the front half and 1 on the back half since the previous owner had the bolt on type clamps that were so tight the leaves wouldn't slide on each other as the spring tried to compress.
Posted By: oldtimer5151
Re: Broken tranny tailshaft housing question - 09/28/12 10:56 PM
You will have to run a pinion snubber about 1 inch from floor. Check rear shocks they may have dents next to the housing.
Posted By: dragnduster
Re: Broken tranny tailshaft housing question - 09/28/12 11:09 PM
I am running a pinion snubber but have it about 3/4" off the floor. I will check the shocks for dents, thanks for the help.
Posted By: Sport440
Re: Broken tranny tailshaft housing question - 09/28/12 11:22 PM
You stated that your driveshaft is 3/4" shorter then you would like it. What is that number? At rest I like it to be 3/4" max.
Posted By: J_BODY
Re: Broken tranny tailshaft housing question - 09/29/12 12:23 AM
Went through a phase of breaking these a few years ago. checked driveshaft at the shop that made it...Ok, Changed trans mount from stock to urethane piece, and checked length and pinion angle... broke one. Added an engine limiter and snub bars to the cage... broke one. Had the drive shaft checked for balance and out of round at another shop... said it was "ok", broke another one. Ordered a brand new aluminum shaft from Inland Empire Driveline... never broke a tail again.
It was funny... the change that I made was putting my newly ported heads on and went from running high tens, to low tens/high nines.
Posted By: eds dart
Re: Broken tranny tailshaft housing question - 09/29/12 12:30 AM
last year on the wednesday test and tune before Monster Mopar. broke on the launch, never knew it. i oiled down the entire length of the track, i couldn,t apologise enough. had made a 4 link change and thought that was the cause, letting yoke bottom in tranny. what happenned is engine limiter mount bolt had nut come loose allowing eng/tranny to move enough to bottom yoke out. i check that nut alot now.
Posted By: dragnduster
Re: Broken tranny tailshaft housing question - 09/29/12 02:22 AM
Here is a couple of pics. The yoke has about 5" of spline with 3.25" of it engaged on the output shaft and 1.75" hanging off the end of the output shaft with the car at rest with weight on its tires. Do you guys think maybe the shaft is too short? Just to clearify this is a stock low compression 440 short block with a set of 906 heads and Comp magnum 292H cam, 2800rpm convertor and a stock tranny. Thanks again for all your help.
Posted By: dragnduster
Re: Broken tranny tailshaft housing question - 09/29/12 02:23 AM
one more with the tail shaft housing slid back into place to show how far the yoke is into the tranny.
Posted By: barracudabob
Re: Broken tranny tailshaft housing question - 09/29/12 02:40 AM
I had the same problem after buying a driveshaft from a reputable shop. Took the shaft to another shop, they said it was out a tiny bit. They fixed it and no more problem.
In your case, I think your shaft is a little too short. you might have to get a new one made up.
Posted By: Sport440
Re: Broken tranny tailshaft housing question - 09/29/12 03:19 AM
Quote:
one more with the tail shaft housing slid back into place to show how far the yoke is into the tranny.
Pics can be deceiving, but from my view your shaft is to short even with your snub nose seal. I see a angle difference between your shaft and housing, Your rear bushing is probably wore out too, adding to that angle.
Add extra shaft pull out on decell, and I see a good chance for shaft wobble on a performance car such as yours. If thats the case your new shaft may be bent now as well.
With your stock springs and loose clamps, Im sure your having alot of axel rotation, Im not 100% positive, but I think you may of found your gremlins.
Short shaft, worn bushing and loose spring wrap control.
Posted By: dragnduster
Re: Broken tranny tailshaft housing question - 09/29/12 03:44 AM
Thanks for the input, guess I better get the driveshaft checked out and maybe even a new tube to make it a little longer. How far into the tranny do you want the yoke to go? Should I be using the bolt on spring clamps and keeping the leaves really tight on each other?
Posted By: THE GLASS MAN
Re: Broken tranny tailshaft housing question - 09/29/12 05:03 AM
You state that you are running a pinion snubber. Pinion snubbers and S/S springs are not to be run together. They will load and unload many times on the track.
Posted By: dragnduster
Re: Broken tranny tailshaft housing question - 09/29/12 04:45 PM
Quote:
You state that you are running a pinion snubber. Pinion snubbers and S/S springs are not to be run together. They will load and unload many times on the track.
Nope, no S/S springs here just standard A body leaf springs.
Posted By: marvo451
Re: Broken tranny tailshaft housing question - 09/29/12 06:39 PM
The old Direct Connection manual said the correct driveshaft length was determined by measuring from the rear of the tailshaft to the center of the rear end yoke bearing cup minus 3.5"
Posted By: dragnduster
Re: Broken tranny tailshaft housing question - 09/29/12 07:09 PM
Quote:
The old Direct Connection manual said the correct driveshaft length was determined by measuring from the rear of the tailshaft to the center of the rear end yoke bearing cup minus 3.5"
Thank you, that will help me on trying to figure out how short my driveshaft is.